Milan Dinić

Change Core Slugs is a plugin that allows you to set custom permalink slugs instead of default ones that are provided with WordPress core. This functionality is already available in WordPress, however it can be used by manually setting new configuration in the code. What this plugin does is that it provides friendly user interface where all site admins can change default slugs.
You can change:
<ul>
<li><code>author</code> base in authors archives</li>
<li><code>search</code> base in searches archives</li>
<li><code>page</code> base in pagination pages of archives or in single posts</li>
<li><code>comments-page</code> base in pagination pages of single posts comments</li>
<li><code>comments</code> base in comments feeds</li>
<li><code>feed</code> base in feeds</li>
</ul>
When you change any slug, you will not get redirection from the pages that used old slug. Same goes if you again change any slug. If you want redirection, you must set it through server rules or with other plugins.
If you disable this plugin, old, default slugs will be restored and URLs with new slugs will stop working. The only way to keep new slugs is by manually setting them in the code.
NOTE: because of two bugs in WordPress core, in some cases setting custom slugs will not work properly. These cases are when <code>page</code> or <code>comments-page</code> include any non-ASCII character (ticket <a href="https://core.trac.wordpress.org/ticket/41891" rel="nofollow ugc">#41891</a>), or when <code>feed</code> or <code>comments</code> bases are set (ticket <a href="https://core.trac.wordpress.org/ticket/43274" rel="nofollow ugc">#43274</a>). Until these two bugs are fixed, you can use <a href="https://github.com/dimadin/redirect-canonical-fix" rel="nofollow ugc">temporary plugin</a> that includes fixes. You do not need that plugin if you do not use features that trigger bugs from above.
And it’s on <a href="https://github.com/dimadin/change-core-slugs" rel="nofollow ugc">GitHub</a>.
<h3>Usage</h3>
Got to Settings > Change Core Slugs page.

Change Core Slugs

Set custom permalink slugs instead of default ones.

texttheater

NOTE: recent WordPress versions already properly transliterate umlauts if the 
site language is German. In that case, German Slugs is no longer needed.
While creating a post or page, WordPress automatically suggests a permalink. If 
your permalink structure contains the %postname% tag, then the title of your 
post or page will be used, simplified by conversion to lowercase, replacing 
spaces with hyphens, removing certain punctuation characters and removing 
diacritics from latin letters.
Thus, by default, ä is replaced with a, ö with o, ü with u and ß with s (similar 
for capital letters). For German, the conventional transliteration is ä to ae, ö 
to oe, ü to ue and ß to ss (sometimes sz in Austria, this is not yet supported). 
This plugin makes your WordPress apply the conventional transliteration.
I wrote this plugin because manually correcting WordPress’s suggestions is a 
considerable hassle, especially if you decide to change the title afterwards.
<h3>Support</h3>
If you have questions or suggestions, contact me at poststelle ät texttheater döt 
net.

German Slugs

German Slugs properly transliterates umlauts and the letter ß appearing in titles for slugs (i.e. for pretty permalinks).

Change Core Slugs vs German Slugs